This invention relates to printing resinous block copolymers. More particularly, this invention relates to printing antiblocking resinous block copolymers containing antiblocking agent.
Many plastic materials exhibit surface characteristics such that printing inks, labels, and the like, do not adhere satisfactorily to the surface of the plastic. In many instances it is possible to improve the adherence characteristics of the substrate by subjecting same to an oxidative print treatment technique utilizing a flame, and corona discharge, an oxidizing acid, or the like. One new class of polymers, resinous block copolymers, is becoming of increasing significance. In many instances these polymers require an antiblocking agent to prevent surfaces thereof from sticking together. One such antiblocking agent is microcrystalline wax as disclosed in U.S. Pat. No. 3,766,114, the disclosure of which is incorporated herein by reference. With such polymers conventional print treatment techniques are not entirely satisfactory because of the presence of the antiblock agent which not only prevents the surface of the polymer from sticking together but also prevents the adherence of printing inks, labels, and the like, even after a standard print treatment.
When standard inks are used to print on resinous block copolymers that contain an antiblocking agent the printed article will not dry well. When the antiblocking agent is microcrystalline wax the standard solvents in the ink soften the wax leaving the surface sticky and unable to dry.
Different methods have been used to render these resinous block copolymers printable. For example, U.S. Pat. No. 3,896,068 and U.S. Pat. No. 4,009,295 disclose the incorporation of an olefin polymer into the resinous block copolymer to render it printable.